Folding documents prior to inserting them into an envelope for mailing is an important task in mass mailing. In large volumes, a folding machine can be used. Folding machines are well known. For example, U.S. Pat. No. 4,701,233 (Beck et al.) discloses a method of folding a sheet by bulging a portion of the sheet and then folding the bulged portion through a roller nip. U.S. Pat. No. 4,875,965 (Marzullo) discloses a folding apparatus wherein a buckle chute is used for stopping a sheet, causing the sheet to enter a roller nip for folding. U.S. Pat. No. 4,944,131 (Gough) also discloses a folding apparatus having a buckle chute. Folding machines are generally designed for folding enclosure material to be inserted into envelopes in an envelope-inserting device.
Folding machines are also designed for making self-mailers. A self-mailer is conventionally defined as a mailpiece without an envelope. The mailer usually contains one or more sheets of printed material, folded once or twice by a folding machine into a smaller piece for mailing. The folded material has a folded end and an open end. The open end is sealed with one or more tabs before the self-mailer is sent to the addressee. In addition, it may be required for an address label and a postage stamp or indicia to be applied to or printed on the folded material. Thus, the components of a commercially available equipment for self mailers can generally be grouped into a printer, a folding machine, a labeler and a tabbing device. The folding machines for making self-mailers are disposed in U.S. Pat. No. 6,702,284 (Sette et al.), for example.
The folding machines as disclosed in the above-mentioned references are separate units in a mailing system in that they are used to fold the printed materials after the printing process is completed. One of the major advantages of these folding machines is that the printed materials or inserted documents do not require creasing prior to folding. However, the device for simultaneous creasing and folding, in general, is mechanically complex.
For a mail preparer with a small volume of mail, he or she usually hand folds the documents to be inserted. Typically a C-fold or Z-fold is made on the documents for a #10 envelope. Unlike folding the documents in half where one can line up one edge with the opposite edge, folding in thirds must be approximated. If the approximation is off, the address may not be clearly visible in a windowed-envelope, or the insert may not fit in the envelope. It is thus desirable and advantageous to provide a method and device for creasing the inserted documents in a cost-effective way to facilitate subsequent folding by hand.